Manufacture of alloys



Patented Nov. 29, 1938 TENT OFFHCE 2,138,459 MANUFACTURE or ALLOYS Leonard Bessemer Pieil, Edgbaston, Birmingham, England, assignor to The International Nickel Company, Inc., New York, N. Y., a corporation of Delaware No Drawing. Application March 28, 1936, Serial No. 71,451. In Great Britain April 3, 1935 17 Claims.

treat a bath of molten metal or alloy with highly reactive substances, generally for the purpose of eliminating impurities therein or to render such impurities innocuous in the solid metalv or alloy. Thus for example, alkaline earth met.- als have been added to nickel alloys for this purpose. In order to ensure that the effect of such deleterious impurities shall be entirely removed, it is in general necessary that an excess of the added substances be present up to the 8 time of solidification of the melt. In many cases,

' ficient time has been allowed for the desired however, the presence of more than a trace of the added substance may itself'have objectionable efiects. Moreover, highly reactive sub-' stances such as those under consideration may be capable of reacting with more than one impurity present and the desired effect on the more deleterious impurity may be minimized by reaction with another. Wastage may also occur by reaction with the air, slags and so forth. Although many proposals have been made, none, as far as I am aware, has been wholly satisfactory and successful, especially when carried into practice on an industrial scale.

The present invention aims at the production of the full desired efiects of the added substances without more than. a predetermined innocuous residual amount remaining in the solid metal or alloy which has been treated.

It is an object of the present invention to provide a process for the production of metals and alloys in which the solid metal or alloy contains a predetermined amount of a highly reactive substance.

The invention also contemplates the provision of a process which can be conveniently carried into practice on an industrial scale for effecting the precise addition of a predetermined residual amount of a highly reactive substance in the finished solid metal or alloy.

Other objects and advantages of the invention will become apparent from the following description.

Broadly stated, the present invention contemplates that the molten metal is first treated with an excess of one or more of the highly reactive substances or equivalent substances. After sufreaction to proceed the excess is removed or neutralized in such a way as not to introduce any harmful impurities into the melt. Finally the desired amount of the highly reactive substance or substances is added, and in order to protect it from possible coincident chemical reactions such as oxidation, a protecting agent may be added at the same time in the form of an element which would take part in these chemical reactions more easily than the highly reactive substance. This protecting agent must be such that any residue of it would not be objectionable in the finished alloy. By equivalent substance is meant a substance which will enter into chemical reaction with the same types 'of impurity as would the highly reactive substance or substances which is or are intended to be retained in the final alloy. Thus, as an example, if calcium is the desired highly reactive substance, the firstaddition may consist of cerium, or cerium and calcium. It will be understood that the molten metal may be held for a considerable time with the excess of the highly reactive substance in it in order to ensure complete interaction with the deleterious impurities present. The stage at which the excess of highly reactive substance just vanishes can often be seen by a change in the appearance of the surface of the molten material, as will be understood by those skilled in the art.

For the purpose of giving those skilled in the art a better understanding 'of the invention, the

calcium and silicon alloy containing 25% calcium) may lead to either an excess or a deficiency of calcium in accordance with the amount that is-lost by oxidation and other reactions, and in either case to an alloy that is not as easily forgeable as it might be. In proceeding in accordance with the present invention, how'- ever, the melt may first be treated with an excess of calcium, the amount being determined to some extent in accordance with the quantity of impurities, and particularly the oxygen, nitrogen and sulphur, likely to be present, and also with the furnace conditions. The quantity of calcium necessary may be reduced by the preliminary or simultaneous addition of aluminum,

cess calcium and yet be readily removable; for instance, sulphur, phosphorus or arsenic may be added to form calcium-sulphur, calcium-phosphorus or calcium-arsenic compounds respectively and any excess sulphur, phosphorus or arsenic may be neutralized by magnesium. Again. the molten metal may be treated with an oxide, such as nickel or chromium oxide. Alternatively, the surface is simply exposed to the atmosphere, so that the calcium is oxidized and when the excess calcium is substantially all removed, the final treatment with calcium is carried out. To pretrative examples.

Example N0. 1

After a preliminary addition of about 0.5 per cent. manganese and 0.2 per cent. silicon has been made to a bath containing about one thousand pounds of molten nickel-chromium alloy comprising about per cent. nickel and 20 per cent. chromium, about 0.5 per cent. calcium silicide containing about 0.125 per cent. calcium is added. The melt is then held for about five minutes whilst the calcium interacts with impurities present and excess calcium is removed by interaction with atmospheric oxygen. During this time, the melt is adjusted to the correct casting temperature and the molten metal is then poured into a ladle. About 0.05 per cent. arsenic is then added to clean up any excess calcium .which still remains and finally an addition of 0.25 per cent. calcium silicide is made. The metal is thereupon cast into ingots and a residual content of 0.05 per cent. calcium is obtained.

If the molten metal, in being poured into the mould, is unduly exposed to the air as, for ex ample, when very small ingots are to be cast, the final addition of calcium silicide may be immediately preceded, accompanied or immediately followed by the addition of about 0.15 per cent. cerium.

Example No. 2

Preliminary deoxidation of a one thousand pound melt of nickel-chromium alloy as in Example No. 1, is carried out by adding 0.3 per cent. calcium silicide. An addition of 0.10 per cent. cerium is then made and a period of three minutes allowed for complete reaction to take place. During this period the whole of the calcium and the bulk of the cerium are consumed by oxidation or other reactions. The melt is then poured into a ladle, a final addition of 0.15 per cent. cerium is made and immediately afterwards the metal is cast into ingots. These contain the desired amount of 0.16.% cerium.

Although the present invention has been described in conjunction with nickel alloys it is to be understood that it is not limited thereto and may be applied to other alloys. Furthermore, the invention is not restricted to the addition of calcium or cerium to alloys, but may be applied to the addition of other elements, such as the other alkaline-earth metals, the other raw earth metals, thorium, hafnium, beryllium, niobium, tantalum, titanium, lithium and zirconium,

. that variations and modifications are within the purview of the invention and are within the scope of the appended claims.

I claim:

1. The process for the consistent production of nickel and nickel alloys containing predetermined and controlled amounts of calcium which comprises establishing a. nickel-containing molten bath containing deleterious impurities,

adding manganese and silicon for preliminary deoxidation, adding sufficient calcium silicide containing. about 25% calcium to react with residual impurities and to provide an excess of calcium, holding the melt until said calcium reacts completely with said impurities and a portion of the excess of calcium is removed by interaction with oxygen while adjusting the temperature of said bath to a casting temperature, pouring said molten metal into a ladle, adding suflicient arsenic to react with any excess of calcium thereby producing a bath of molten metal substantially devoid of deleterious impurities and unreacted calcium, adding a predetermined and controlled amount of calcium silicide containing about 25% calcium sufficient to produce a molten metal containing about 0.05% calcium and pouring said molten metal whereby sound nickel-containing castings having about 0.05% calcium are consistently produced.

2. The process for the consistent production of nickel and nickel alloys containing predetermined and controlled amounts of calcium which comprises adding about 0.5% manganese and about 0.2% silicon by weight to a molten metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities, adding about 0.5% by weight of calcium silicide containing about 25% calcium to react with deleterious impurities and provide an excess of calcium, holding the melt until said calcium reacts with said impurities, causing any excess of calcium to react with atmospheric oxygen and arsenic to render said calcium innocuous and to produce a molten bath substantially devoid of deleterious impurities and unreacted calcium, and adding a predetermined and controlled amount of calcium silicide containing about 25% calcium sufllcient to produce a melt containing about 0.05% calcium whereby sound castings of nickel and nickel alloys containing about 0.05% calcium are consistently produced.

3. The process for the consistent production of nickel and nickel alloys containing predetermined and controlled amounts of cerium which comprises adding an amount of calcium silicide containing 25% calcium in excess of the quantity required for preliminary deoxidation to a molten bath of ametal selected from the group consistingof nickel and nickel alloys and containing deleterious impurities, adding about 0.10% eerium by weight to said metal bath, holding said bath of molten metal until the cerium has reacted completely with said impurities, the calcium and the bulk of the cerium have been rendered innocuous thereby producing a bath sub- 75 stantialiy devoid of deleterious impurities and unreacted calcium and cerium and adding a predetermined and controlled amount of cerium to produce castings of nickel and nickel alloys containing about 0.16% cerium whereby sound nickel and nickel alloy castings are consistently produced.

4. The process for the consistent production of nickel and nickel alloys containing small, predetermined and controlled amounts or cerium which comprises establishing a molten bath of metal selected from the group consisting of nickel and nickel alloys, and containing deleterious impurities including oxides and gases, adding to the nickel mass a reactive calcium agent in an amount to assure an unconsumed excess after preliminary deoxidation, adding a reactive cerium agent to said nickel mass in an amount equivalent, to about 0.10% cerium by weight of the metal in the bath, holding said bath of molten metal until the reactive cerium agent has reacted completely with said impurities and leaves an unconsumed excess, neutralizing said unconsumed excess of the reactive calcium agent and the reactive cerium agentimpurities, including oxides and gases; adding to the molten nickel mass a highly reactive addition agent selected from the group consisting of the rare earth metals, the alkaline earth metals, thorium, hafnium, beryllium, niobium, tantalum, titanium, lithium, and zirconium in an amount to assure an unconsumed excess after reacting with said deleterious impurities; holding said bath of molten metal at efiective temperatures until said highly reactive addition agent has reacted completely with said deleterious impurities; neutralizing the unconsumed excess of said highly reactive addition agent thereby producing a bath substantially devoid of deleterious impurities and unconsumed highly reactive addition agent; and adding a small, predetermined and controlled amount of reactive cerium agent to produce castings containing about 0.16% cerium whereby sound nickel and nickel alloy castings} containing a small, predetermined and controlled amount of cerium are consistently produced.

6. The process for the consistent production of nickel and nickel alloys containing small, predetermined and controlled amounts of highly reactive addition agents which comprises establishing a molten bath of metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities including oxides and gases, adding a highly reactive cerium agent to the nickel mass in an amount to assure an unconsumed excess after reacting with said deleterious impurities, holding said molten nickel mass until said reactive cerium agent has reacted with said deleterious impurities and leaves an excess of cerium, introducing an agent to neutralize the excess of unconsumed cerium thereby producing a molten nickel mass substantially devoid of deleterious impurities and unconsumed reactive cerium and adding a small predetermined and controlled amount of reactive cerium agent substantially equivalent to the small desired concentration of unconsumed cerium in the finished product whereby nickel and nickel alloys containing small, predetermined and controlled amounts of cerium are consistently produced substantially without the loss of unsuitable heats.

'7. The process for the consistent production of nickel and nickel alloys containing small, predetermined and controlled amounts of cerium which comprises establishing a molten bath of metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities, including oxides and gases; adding to the molten nickel mass a highly reactive addition agent selected from the group consisting of the rare earth metals, the alkaline earth metals, thorium, hafnium, beryllium, niobium, tantalum, titanium, lithium, and zirconium in an amount to assure an unconsumed excess after reacting with said deleterious impurities; holding said molten nickel mass at efiective temperatures until said highly reactive addition agent has reacted completely with said deleterious impurities; neutralizing the unconsumed excess of said highly reactive addition agent thereby producing a bath substantially devoid of deleterious impurities and unconsumed highly reactive addition agent; and adding a small, predetermined and controlled amount of reactive .cerium agent approximately equivalent to the quantity of unconsumed reactive cerium desired in the product whereby nickel and nickel alloys containing a small, predetermined and controlled amount of cerium are consistently produced.

8. The process for the consistent production of nickel and nickel alloys containing small predetermined and controlled amounts of a highly reactive addition agent which comprises preliminarily deoxidizing a molten bath of metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities including oxides and gases; adding to the nickel mass a highly reactive addition agent selected from the group consisting of the rare earth'metals, the alkaline earth metals, thorium, hafnium, beryllium, niobium, tantalum, titanium, lithium and zirconium in an amount to assure an unconsumed excess after reacting with said deleterious impurities; holding said molten bath until said highly reactive addition agent has reacted with said impurities; introducing an agent to neutralize said unconsumedexcess of highly reactive addition agent thereby producing a molten bath substantially devoid of deleterious impurities and unconsumed highly reactive addition agent; adding a small, predetermined and controlled amount of a reactive calcium agent sufiicient to produce a melt containing about 0.05% calcium; and casting said melt in the presence of at least one of the metals of the group consisting of cerium, aluminum, lithium and zirconium whereby sound nickel and nickel alloy castings containing about 0.05% calcium are consistently produced.

9. The process for the consistent production of nickel and nickel alloys containing small, predetermined and controlled amounts of highly reactive addition agents which comprises estab- ,lishing a molten bath of metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities including oxides and gases; adding to the molten nickel mass in the presence of at least one element of the group consisting of aluminium, zirconium, cirium and lithium a reactive calcium agent in an amount to assure an unconsumed excess of calcium after reacting with said deleterious impurities, holding said bath until said calcium agent reacts completely with said deleterious impurities, and leaves an excess of unconsumed reactive calcium, introducing an agent to neutralize said excess of unconsumed reactive calcium agent thereby producing a molten nickel mass substantially devoid of said deleterious impurities and unconsumed reactive calcium, thereafter adding a reactive calcium agent containing an amount of calcium exactly equal to that small, predetermined and controlled amount desired in the finished product and pouring said molten nickel mass containing said exact amount of unconsumed reactive calcium in the presence of at least one member of the group consisting of cerium, aluminum, lithium and zirconium whereby nickel and nickel alloys containing small, predetermined and controlled amounts of calcium are produced substantially without loss due to unsuitable heats.

10. The process for the consistent production of nickel and nickel alloys containing small, predetermined and controlled amounts of highly reactive addition agents which comprises adding to a bath of molten metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities, including oxides and gases, a reactive calcium agent in the presence of at least one member of the group consisting of aluminium, zirconium, cerium and lithium and in an amount to assure an excess of unconsumed reactive calcium agent after reacting with said deleterious impurities, holding said bath until said calcium reacts completely with said deleterious impurities and leaves an excess of unconsumed reactive calcium, introducing sufiicient arsenic to neutralize said excessof unconsumed reactive calcium thereby producing a molten nickel mass substantially devoid of deleterious impurities and unconsumed reactive calcium and thereafter adding an amount of reactive calcium agent aqual to that small, predetermined and controlled amount desired in the finished product whereby nickel and nickel alloys containing a small, predetermined and controlled amount of calcium are consistently produced substantially without the production of unsuitable heats.

11. The process for the consistent production of nickel and nickel alloys containing small, predetermined and controlled amounts of highly reactive addition agents substantially without the production of unsuitable heats which comprises adding to a molten bath of metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities, including oxides and gases, a reactive calcium agent capable of reacting with said impurities and in an amount to assure an, unconsumed excess after reacting with said impurities, holding said bath containing said excess of unconsumed reactive calcium agent until said calcium agent reacts completely with said impurities and leaves an excess of calcium, introducing an agent selected from the group consisting of sulphur, phosphorus, arsenic, atmospheric air, and metal oxides reable heats.

12. The process for the consistent production of nickel and nickel alloys containing desirable predetermined and controlled amounts of highly reactive addition agents which comprises establishing a molten bath of metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities including oxides and gases, adding a highly reactive addition agent selected from the group consisting of the rare earth metals, the alkaline earth metals, thorium, hafnium, beryllium, niobium, tantalum, titanium, lithium and zirconium to react with said impurities and in an amount to assure an unconsumed excess after reacting with said deleterious impurities, holding said molten mass of nickel containing said unconsumed excess of highly reactive addition agent at an efiective temperature until said addition agent has reacted completely with said deleterious impurities, introducing an agent selected from the group consisting of sulphur, phosphorus, arsenic, atmospheric air, and metal oxides reducible by the highly reactive addition agent into the molten nickel mass to react with the unconsumed excess of highly reactive addition agent to neutralize said excess of highly reactive addition agent thereby producing a molten nickel mass substantially devoid of deleterious impurities and unconsumed highly reactive addition agent, and adding a highly reactive addition agent selected from the group consisting of the rare earth metals, the alikaline earth metals, thorium, hafnium, beryllium, niobium, tantalum, titanium, lithium and zirconium in an amount corresponding to that small, predetermined and controlled concentration of said highly reactive addition agent which is desired in the finished product whereby nickel and nickel alloys containing small predetermined and controlled amounts of highly reactive addition agent are consistently produced substantially without loss of unsuitable heats.

13. The process for the consistent production of nickel and nickel alloys containing small predetermined and controlled amounts of highly reactive addition agents substantially without loss of unsuitable heats which comprises adding a deoxidizing agent other than a highly reactive' addition agent desired in the finished product to a molten bath of metal selected from the groupconsisti'ng of nickel and nickel alloys and containing deleterious impurities including oxides and gases to obtain a preliminary deoxidation, adding a highly reactive addition agent selected from the group consisting of the rare earth metals, the alkaline earth metals, thorium, hafnium, beryllium, niobium, tantalum, titanium, lithium and zirconium to react with impurities and in an amount to assure an excess after reacting with deleterious impurities, holding said bath at an effective temperature until said highly reactive addition agent has reacted completely with said deleterious impurities leaving an unconsumed excess of said highly reactive addition agent in said bath, introducing an agent to react with the unconsumed excess of highly reactive addition agent to neutralize said unconsumed excess of highly reactive addition agent'and to produce a molten nickel mass substantially devoid of deleterious impurities and unconsumed highly reactive addition agent, and adding a highly reactive addition agent selected from the group consisting of the rare earth metals, the alkaline earth metals, thorium, hafnium, beryllium, niobium, tantalum, titanium, lithium and zirconium in an amount equal to that small, predetermined and controlled amount of highly reactive addition agent desired in the final product whereby nickel and nickel alloys containing exact predetermined and controlled amounts of highly reactive addition agent are consistently produced substantially without loss of unsuitable heats.

14. The process for the consistent production of nickel and nickel alloys containing small, predetermined and controlled amounts of highly reactive addition agents substantially without the production of unsuitable heats which comprises adding to a molten bath of metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities, including oxides and gases, a highly reactive addition agent selected from the group consisting of the rare earth metals, the alkaline earth metals, thorium, hafnium, beryllium, niobium, tantalum, tatanium, lithium and zirconium to react with said deleterious impurities and in an amount to assure an unconsumed excess after reacting with said impurities, holding said bath containing the excess of said highly reactive addition agent until said addition agent has reacted completely with said deleterious impurities thereby producing a molten bath substantially devoid of impurities, introducing an agent to neutralize the excess of unconsumed highly reactive addition agent thereby producing a molten nickel mass substantially devoid of deleterious impurities and unconsumed highly reactive addition agent, and adding a highly reactive addition agent selected from the group consisting of the rare earth metals, the alkaline earth metals, thorium, hafnium, beryllium, niobium, tantalum, titanium, lithium and zirconium in an amount equivalent to that small, predetermined and controlled amount desired in the finished product whereby nickel and nickel alloys containing small predetermined and controlled amounts of highly reactive addition agent having a favorable effect upon the properties of the finished product are consistently produced substantially without the production of unsuitable heats.

15. The process for the consistent production of nickel and nickel alloys containing small, predetermined and controlled amounts of highly reactive addition agent which comprises adding to a molten bath of metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities, including oxides and gases, an addition agent capable of reacting with said impurities and in an amount to assure an unconsumed excess over the stoichiometric quantity required to interact with said impurities, maintaining said molten nickel mass at an eifective temperature while said addition agent reacts with said impurities thereby producing a molten bath substantially devoid of said impurities, introducing an agent to react with the unconsumed excess of said highly reactive addition agent to neutralize substantially all of said unconsumed excess thereby producing a molten nickel mass substantially devoid of deleterious impurities and unconsumedhighly reactive addition agent, and adding a highly reactive addition agent in an amount equal to the desired predetermined and controlled concentration of said highly reactive addition agent to be contained in the product, whereby nickel and nickel alloys containing small, predetermined and controlled amounts of highly reactive addition agents are consistently produced.

16. The process for the consistent production of nickel and nickel alloys containing small, predetermined and controlled residual amounts of highly reactive addition agent which comprises adding to a bath of molten metal selected from the group consisting of nickel and nickel alloys and containing deleterious impurities, including oxides and gases, an addition agent capable of reacting with said impurities and in an amount to assure an unconsumed excess after reacting with said impurities, neutralizing said unconsumed excess of highly reactive addition agent and finally adding to the molten nickel mass a small, predetermined and controlled amount of highly reactive addition agent substantially equal to that desired in the product whereby a nickel mass is consistently produced containing a small, predetermined and controlled amount of highly reactive addition agent.

17. The process for the consistent production of metals and alloys containing small, predetermined and controlled residual amounts of highly reactive addition agent which comprises adding to a bath of molten metal containing deleterious impurities including oxides and gases, an addition agent capable of reacting with said impurities and in an amount to assure an unconsumed excess after reacting with said impurities, neutralizing said unconsumed excess of reactive addition agent and finally adding to the molten metal a small, predetermined and controlled amount of highly reactive addition agent substantially equal to that desired in the product whereby metals and alloys are consistently produced containing a small, predetermined and controlled amount of highly reactive addition agent.

LEONARD BESSEMER PFEIL. 

